Enameling and varnishing wire, ribbons, and the like



. March 1, 1938. w, ANKLI 2,110,011

ENAMELING AND VARNISHING V-VIRES, RIBBONS, AND THE LIKE Filed Oct. 24, 1934 Patented Mar. 1,1938

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it so Walter inc li, Fiarcelcna, dpaln, assignor tc insnlatus it. ill, Mug, fiwitaerland, a joint-stitch company oi Swltnerlantil Application ilictober 2th wi l, denial hie. l lilt'itt in Germany iictoher til, Mitt 2 Claims.

I'he present invention concerns a process and a device for enameling and varnishing wires, strips or the like.

in the enameling processes known hitherto the 5 wire or strip is allowed to pass along a member to which the solution to be applied is fed by any appropriate means. The first coating of enamel which is thus applied on the wire is dried in an oven, after which the wire receives a fresh coating by passing it again over the same member and so forth, until the enameling operation is completed. The first coating of enamel is thus subjected to the drying operation as many times as the wire receives successive coatings. in the i5 enameling processes known hitherto, the first coating of enamel is by far the thinnest and consequently the most fragile, which according to experiment must be due to the fact that the coat-= ing of enamel which has set is all the thinner as the diameter of the wire is smaller. in other words it has thus been established that in the mass in which the diameter increases, the thickness of the coating of enamel which has set likewise increases. It results from the foregoing, on

the one hand, that the first coating of enamel is the thinnest, and the successively applied coatings increase in thickness and, on the other hand, that the thickest coating is precisely the one which is the least subjected to the oven- 3li drying operation.

It results furthermore that under these conditions of enameling and drying, the total mass of enamel distributed around the wireis not homogeneous. Owing to this and to the fact that the 35 first coating is very thin and is treated to too much in the drying oven, said coating does not adhere sufficiently to the conducting wire and can even become completely separated from the latter in the form of a tube. Furthermore the dif- 40 ferent layers do not have the same dielectric resistance, and from layer to layer there is a different resistance to acids and benzol.

With the process of enameling or varnishing according to the invention, these drawbacks are e 45 overcome by the fact that successive layers of decreasing thickness are applied on the wire or the strip to be treated.

The invention furthermore concerns a device for carrying out the above process. Said device 50 essentially comprises a roller over which the wire passes several times at points spaced apart along its generatrix and on which a solution of enamel of insulating material is applied, the quantity of which decreases from one end to the other of the 55 vroller.

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According to one embodiment, the. roller is covered with felt or other absorbent material and rotates slowly above a bath of solution of enamel or insulating material in which it dips deeper at one end than at the other.

Other characteristics and pecularities will become apparent i'rorn the ensuing description and the drawing.

in the latter:

Fig. l is the view of a device for carrying out the enameling process according to the invention.

Fig. 2 is a plan view of the enamel applying means.

Fig. 3 is a side view in section-along the lines m--llii oi Fig. 2.

The apparatus shown diagrammatically in the drawing essentially comprises a container l for the solution of enamel or insulating material with which the wire or ribbon is to be coated, and also in the upper part of said container a conical roller which. rotates slowly about a spindle 2. According to the invention, the roller is covered with felt or other absorbent material. As seen in Fig. l, the lower generatrix t of the roller clips at varying depth into the bath of solution t. Furthermore, as seen in Fig. 2, the roller is arranged so that its lateral generatrix t is located outside the container i. The wire'or strip, indicated at the various positions by a, a, b, b, c, 0', cl, d, and e to be coated passes against this lateral generatrix. The place where the wire first passes over the roller 3 is shown by a line or point a respectively, i. e. the wire passes first of all along the portion of the conical roller 3 which has the largest diameter. it thus receives a first coating of enamel. Thereupon the wire is dried by the drier l, and then passes at the line b a second time over the roller 3, whereby it receives the second coating of enamel. After the second coating the wire is again dried, whereupon the process is continued in the same way up to the last coating. In the example illustrated, it has been as-v sumed that five successive coatings are applied, but obviously this number is quite arbitrary and is only an example, which can be varied according to circumstances.

As can be seen in the device described, the wire in the position a comes in contact with that part of the roller which receives the greatest quantity of enamel solution, since the corresponding end of the roller 3, dips deepest into the bath. Under these conditions the layer of enamel which is deposited on the line a has the greatest thickness. The thickness of the second coating deposited on the line b is slightly less, and so on up to the fifth and last coating.

By means of the process according to the invention, a mass of enamel or insulating material is thus obtained, the successive layers of which decrease in thickness, and the thickest layers of which are subjected the most often to the action of oven drying. In this manner a perfectly homogeneous coating of enamel or insulating material is obtained, which adheres strongly to the wire.

It is pointed out that the embodiment of the device illustrated in the drawing is only a practical example and that the process according to the invention could be carried out by means of different devices. The essential characteristic of the device consists in the fact that the quantity of enamel solution distributed over the roller varies from point to point along its generatrix.

It is obvious that the invention is only described and illustrated as a practical example which only serves for the explanation and to which the invention is not limited. Modifications of detail could be made therein in the spirit of the invention.

I claim:

1. Process of insulating wires for electric purposes, which comprises alternating steps of coating the wire with a liquid composition and then setting said composition on the wire by heat, said coating steps comprising the applying of the liquid composition in successive layers of de creasing thickness.

2. Process of insulating wires for electric purposes, which comprises passing the wire into contact with the surface of a liquid to coat it with a liquid composition, alternating said step with the step of setting said composition on the wire by heat, supplying said liquid surface with said liquid composition, applying the liquid from said liquid surface to said wire in quantities decreasing with each successive application, thereby to coat said wire with successive layers of decreasing thickness.

WALTER LEO ANKLI. 

